Systems and methods for intravascular catheter positioning and/or nerve stimulation

- Lungpacer Medical, Inc.

A method for positioning an intravascular catheter may include inserting the intravascular catheter into a venous system of a patient, wherein the catheter includes a plurality of electrodes, and multiple electrodes of the plurality of electrodes are configured to emit electrical signals; positioning a distal portion of the catheter in a first position; using one or more electrodes of the plurality of electrodes to acquire an ECG signal; based on the acquired ECG signal, adjusting the distal portion of the catheter to a second position different from the first position; identifying at least one first electrode of the plurality of electrodes to stimulate a first nerve; identifying at least one second electrode of the plurality of electrodes to stimulate a second nerve; and stimulating at least one of the first and second nerves to cause a contraction of a respiratory muscle.

Skip to: Description  ·  Claims  ·  References Cited  · Patent History  ·  Patent History
Description
CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. application Ser. No. 15/666,989, filed Aug. 2, 2017, which is hereby incorporated by reference.

TECHNICAL FIELD

This disclosure relates to systems, devices, and methods for one or more of positioning an intravascular nerve stimulation catheter, selecting electrodes for nerve stimulation, or stimulating nerves.

BACKGROUND

Electrical stimulation of nerves may be used to control muscle activity or to generate or attenuate sensations. Nerves and muscles may be stimulated by placing electrodes in, around, or near the nerves and muscles and by activating the electrodes by means of an implanted or external source of energy (e.g., electricity).

The diaphragm muscle provides an important function for the respiration of human beings. The phrenic nerves normally transmit signals from the brain to cause the contractions of the diaphragm muscle necessary for breathing. However, various conditions can prevent appropriate signals from being delivered to the phrenic nerves. These include: permanent or temporary injury or disease affecting the spinal cord or brain stem; Amyotrophic Lateral Sclerosis (ALS); decreased day or night ventilatory drive (e.g., central sleep apnea, Ondine's curse); and decreased ventilatory drive while under the influence of anesthetic agents and/or mechanical ventilation. These conditions affect a significant number of people.

Intubation and positive pressure mechanical ventilation (MV) may be used for periods of several hours or several days, sometimes weeks, to help critically ill patients breathe while in intensive care units (ICU). Some patients may be unable to regain voluntary breathing and thus require prolonged or permanent mechanical ventilation. Although mechanical ventilation can be initially lifesaving, it has a range of significant problems and/or side effects. Mechanical ventilation:

    • often causes ventilator-induced lung injury (VILI) and alveolar damage, which can lead to accumulation of fluid in the lungs and increased susceptibility to infection (ventilator-associated pneumonia, VAP);
    • commonly requires sedation to reduce discomfort and anxiety in acutely intubated patients;
    • leads to rapid atrophy of the disused diaphragm muscle (ventilator-induced diaphragm dysfunction, VIDD);
    • can adversely affect venous return because the lungs are pressurized and the diaphragm is inactive;
    • interferes with eating and speaking;
    • requires apparatus that is not readily portable; and
    • increases the risk of dying if the patient fails to regain normal breathing and becomes ventilator-dependent.

A patient who is sedated and connected to a mechanical ventilator cannot breathe normally because the central neural drive to the diaphragm and accessory respiratory muscles are suppressed. Inactivity leads to muscle disuse atrophy and an overall decline in well-being. Diaphragm muscle atrophy occurs rapidly and can be a serious problem to the patient. According to a published study of organ donor patients (Levine et al., New England Journal of Medicine, 358: 1327-1335, 2008), after only 18 to 69 hours of mechanical ventilation, all diaphragm muscle fibers had shrunk on average by 52-57%. Muscle fiber atrophy results in muscle weakness and increased fatigability. Therefore, ventilator-induced diaphragm atrophy could cause a patient to become ventilator-dependent. It has been estimated that over 600,000 U.S. patients will be ventilator-dependent and require prolonged mechanical ventilation by the year 2020. Zilberberg et al., “Growth in adult prolonged acute mechanical ventilation: implications for healthcare delivery,” Crit Care Med., 2008 May, 36(5): 1451-55.

SUMMARY

Embodiments of the present disclosure relate to, among other things, systems, devices, and methods for one or more of positioning an intravascular nerve stimulation catheter, selecting electrodes for nerve stimulation, or stimulating nerves. Each of the embodiments disclosed herein may include one or more of the features described in connection with any of the other disclosed embodiments.

In one example, a method for positioning an intravascular catheter may include inserting the intravascular catheter into a venous system of a patient, wherein the catheter includes a plurality of electrodes, and multiple electrodes of the plurality of electrodes are configured to emit electrical signals; positioning a distal portion of the catheter in a first position; using one or more electrodes of the plurality of electrodes to acquire an ECG signal; based on the acquired ECG signal, adjusting the distal portion of the catheter to a second position different from the first position; identifying at least one first electrode of the plurality of electrodes to stimulate a first nerve; identifying at least one second electrode of the plurality of electrodes to stimulate a second nerve; and stimulating at least one of the first and second nerves to cause a contraction of a respiratory muscle.

Any method described herein may additionally or alternatively include one or more of the following features or steps: inserting the intravascular catheter into the venous system may include inserting the intravascular catheter into: 1) at least one of a left subclavian, axillary, cephalic, cardiophrenic, brachial, radial, or left jugular vein, and 2) a superior vena cava; the first position may be proximate an atrium of a heart of the patient, and the second position may be in a superior vena cava; the ECG signal may be a first ECG signal, and the method may further comprise using one or more electrodes of the plurality of electrodes to acquire a second ECG signal; the one or more electrodes used to acquire the first ECG signal may be positioned on a proximal portion of the catheter and may be configured to stimulate the first nerve, and the one or more electrodes used to acquire the second ECG signal may be positioned on a distal portion of the catheter and may be configured to stimulate the second nerve; the method may further include comparing the first ECG signal to the second ECG signal, and based on the comparison, adjusting the distal portion of the catheter to the second position; the second position may be farther from a heart of the patient than the first position; the method may further include using one or more electrodes of the plurality of electrodes to sense at least one of an impedance or nerve activity; or each of the at least one first electrode and the at least one second electrode may be a combination of electrodes.

In another example, a method for positioning an intravascular catheter may include inserting the intravascular catheter into: 1) at least one of a left subclavian vein or a left jugular vein, and 2) a superior vena cava, wherein the catheter includes a plurality of electrodes, and the plurality of electrodes includes a proximal set of electrodes positioned proximate a left phrenic nerve and a distal set of electrodes positioned proximate a right phrenic nerve; using one or more electrodes of the plurality of electrodes to acquire an ECG signal; based on a change in the ECG signal, withdrawing the catheter away from a heart of a patient; stimulating the left phrenic nerve using one or more electrodes of the proximal set of electrodes; and stimulating the right phrenic nerve using one or more electrodes of the distal set of electrodes.

Any method described herein may additionally or alternatively include one or more of the following features or steps: the change in the ECG signal may be a change in an amplitude of a P-wave, and the change may occur as a distal end of the catheter enters a region proximate an atrium of the heart; the step of withdrawing the catheter away from the heart may cause a change in the amplitude of the P-wave; the ECG signal may be a first ECG signal acquired by one or more electrodes of the proximal set of electrodes, and the method may further include using one or more electrodes of the distal set of electrodes to acquire a second ECG signal; the method may further include determining a difference between a P-wave of the first ECG signal and a P-wave of the second ECG signal, and withdrawing the catheter away from the heart of the patient when the difference exceeds a predetermined value; the difference may exceed the predetermined value when the catheter is advanced into an atrium of the heart; a hub coupled to the catheter and positioned exterior to the patient may be used with the one or more electrodes of the plurality of electrodes to acquire the ECG signal; or the method may further include monitoring the ECG signal as a distal end of the catheter is inserted into the at least one of the left subclavian vein or the left jugular vein and advanced into the superior vena cava.

In yet another example, a method for positioning an intravascular catheter may include inserting the intravascular catheter into a venous system of a patient, wherein the catheter includes a plurality of proximal electrodes and a plurality of distal electrodes; using one or more electrodes of the plurality of proximal electrodes to acquire a first ECG signal, and using one or more electrodes of the plurality of distal electrodes to acquire a second ECG signal; comparing the first ECG signal to the second ECG signal; based on the comparison between the first ECG signal and the second ECG signal, adjusting a position of the catheter; stimulating the first nerve using one or more of the plurality of proximal electrodes; and stimulating the second nerve using one or more of the plurality of distal electrodes.

Any method described herein may additionally or alternatively include one or more of the following features or steps: the first nerve may be a left phrenic nerve, and the second nerve may be a right phrenic nerve; comparing the first ECG signal to the second ECG signal may include comparing an amplitude of a portion of the first ECG signal to an amplitude of a portion of the second ECG signal; the step of comparing may occur a plurality of times during the inserting step; adjusting the position of the catheter may include moving the catheter away from a heart; at least one of stimulating the first nerve or stimulating the second nerve may cause a contraction of a diaphragm; or the method may further include sensing activity of the first nerve using one or more of the proximal electrodes and sensing activity of the second nerve using one or more of the distal electrodes

In another example, a method for positioning an intravascular catheter may include inserting the intravascular catheter into: 1) at least one of a left subclavian vein or a left jugular vein, and 2) a superior vena cava, wherein the catheter includes a plurality of proximal electrodes configured to be positioned proximate a left phrenic nerve and a plurality of distal electrodes configured to be positioned proximate a right phrenic nerve; at multiple positions of the catheter during the inserting step, using one or more electrodes of the plurality of proximal electrodes to acquire a first ECG signal, and using one or more electrodes of the plurality of distal electrodes to acquire a second ECG signal; comparing the first ECG signal to the second ECG signal at several of the multiple positions; based on the comparisons of the first ECG signal to the second ECG signal, determining a desired position of the catheter for nerve stimulation; stimulating the left phrenic nerve using one or more of the plurality of proximal electrodes; and stimulating the right phrenic nerve using one of more of the plurality of distal electrodes.

Any method described herein may additionally or alternatively include one or more of the following features or steps: the method may further include advancing a distal end of the catheter into a region proximate an atrium of a heart; one of the multiple positions may be a position in which the distal end of the catheter is proximate the atrium of the heart, and in the position, the comparison may indicate a difference between an amplitude of the first ECG signal and an amplitude of the second ECG signal that exceeds a predetermined value; the method may further include moving the catheter away from the heart; stimulating the left phrenic nerve may cause a diaphragm contraction, and stimulating the right phrenic nerve may cause a diaphragm contraction; the proximal electrodes used to acquire the first ECG signal may be configured to stimulate the left phrenic nerve, and the distal electrodes used to acquire the second ECG signal may be configured to stimulate the right phrenic nerve.

It may be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed. As used herein, the terms “comprises,” “comprising,” or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements, but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. The term “exemplary” is used in the sense of “example,” rather than “ideal.”

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the present disclosure and together with the description, serve to explain the principles of the disclosure.

FIG. 1 illustrates a nerve stimulation system with an intravascular catheter positioned within a patient, according to an exemplary embodiment.

FIG. 2 illustrates a nerve stimulation system having a portable control unit, according to an exemplary embodiment.

FIG. 3 illustrates a wireless configuration of a nerve stimulation system, according to an exemplary embodiment.

FIG. 4 illustrates an intravascular catheter having a helical portion, according to an exemplary embodiment.

FIG. 5 illustrates an intravascular catheter having an optical fiber camera, according to an exemplary embodiment.

FIG. 6 illustrates an intravascular catheter having an ultrasound transducer, according to an exemplary embodiment.

FIG. 7 illustrates a block diagram of a nerve stimulation system having an intravascular catheter and a control unit, according to an exemplary embodiment.

 DETAILED DESCRIPTION

When electrically stimulating nerves or muscles, a variety of goals may be considered. First, it may be desirable to place the electrodes in proximity to the phrenic nerves. Second, it may be desirable to avoid placing electrodes in close proximity to the sinoatrial (SA) node, atrioventricular (AV) node, or the His-Purkinje system located in heart tissue, as electrical stimulation of these anatomical features may cause arrhythmia. Third, when using a device that includes multiple electrodes, it may be desirable to identify particular electrodes that are in close proximity to the nerve. Identifying the proper electrodes may minimize the electrical charge required to effectively stimulate the nerves. Finally, as with any medical procedure, the risk of injury to the patient increases with the length and complexity of the medical procedure. Accordingly, it may be desirable to minimize the length of any procedure to electrically stimulate nerves or muscles.

There remains a need for cost-effective, practical, surgically simple, and minimally invasive devices and methods that address one or more of the above goals and can include one or more of a variety of functions, including: determining whether a nerve is the target nerve, stimulating breathing, delivering treatment (e.g., medications), sensing electrical signals from the body (e.g., ECG), sensing internal vascular blood pressure, heart rate, and electrical impedance, and performing tests, such as detecting respiration rate and blood gas levels (e.g, CO2, O2). There is also a need for devices and methods to help patients wean from mechanical ventilation and regain the ability to breathe naturally.

Accordingly, the present disclosure is drawn to systems, devices, and methods for one or more of positioning an intravascular catheter for nerve stimulation, selecting electrodes for nerve stimulation, and stimulating nerves. In particular, embodiments of the present disclosure may use various positioning features to obtain information useful for positioning a transvascular nerve stimulation catheter, or may use information gathered by sensors to select electrodes and parameters for nerve stimulation.

General System Overview

FIG. 1 illustrates a system 10 that includes a transvascular nerve stimulation catheter 12 and a control unit 14. Catheter 12 may include a plurality of electrodes 34. Catheter 12 may be operably connected (e.g., hardwired, wireless, etc.) to a control unit 14. The control unit 14 may be programmed to perform any of the functions described herein in connection with system 10. In some embodiments, the control unit 14 may include a remote controller 16 to allow a patient or health professional to control operation of the control unit 14 at a distance from the control unit 14. The controller 16 may include a handheld device, as illustrated in FIG. 1. In some examples, controller 16 may include a footswitch/pedal, a voice-activated, touch-activated, or pressure-activated switch, or any other form of a remote actuator. The control unit 14 may include a touch screen 18 and may be supported by a cart 20.

During use, a proximal portion of catheter 12 may be positioned in a left subclavian vein 22, and a distal portion of catheter 12 may be positioned in a superior vena cava 24. Positioned in this manner, electrodes 34 on the proximal portion of catheter 12 may be positioned proximate a left phrenic nerve 26, and electrodes 34 on the distal portion of catheter 12 may be positioned proximate a right phrenic nerve 28. Left and right phrenic nerves 26, 28 may innervate a diaphragm 30. Accordingly, catheter 12 may be positioned to electrically stimulate one or both of the left and right phrenic nerves 26, 28 to cause contraction of the diaphragm muscle 30 to initiate or support a patient breath. In other embodiments, the proximal portion of catheter 12 may be positioned in a left jugular vein 32, and the distal portion of catheter 12 may be positioned in superior vena cava 24.

In further examples, catheter 12 can be placed into and advanced through other vessels providing access to the locations adjacent the target nerve(s) (e.g., phrenic nerves), such as: the jugular, axillary, cephalic, cardiophrenic, brachial, or radial veins. In addition, catheter 12 may use other forms of stimulation energy, such as ultrasound, to activate the target nerves. In some examples, the system 10 can target other respiratory muscles (e.g., intercostal) either in addition to, or alternatively to, the diaphragm 30. The energy can be delivered via one or more methods including transvascular, subcutaneous, nerve cuffs, transdermal stimulation, or other techniques known in the field.

FIG. 2 illustrates an alternative example of system 10, in which control unit 14′ is portable. Portable control unit 14′ may include all of the functionality of control unit 14 of FIG. 1, but it may be carried by a patient or other user to provide the patient with more mobility. In addition to carrying the control unit 14′, the patient can wear control unit 14′ on a belt, on other articles of clothing, or around his/her neck, for example. In other examples, control unit 14′ may be mounted to a patient's bed to minimize the footprint of system 10 in the area around the patient, or to provide portable muscle stimulation in the event a bed-ridden patient needs to be transported or moved to another location.

Similar to FIG. 1, the system of FIG. 2 may include a controller 16, shown as a handheld controller 16. Handheld controller 16 may include buttons 17, 19 that can be pressed by a patient or other user to control breathing patterns. In one example, pressing one of buttons 17, 19 can initiate a “sigh” breath, which may cause a greater volume of air to enter the patient's lungs than in a previous breath. A sigh breath may result when electrodes 34 of catheter 12 are directed to stimulate one or more of the phrenic nerves 26, 28 at a higher level than a normal breath (i.e., a stimulation train having a longer duration of stimulation or having pulses with a higher amplitude, pulse width, or frequency). Higher amplitude stimulation pulses can recruit additional nerve fibers, which in turn can engage additional muscle fibers to cause stronger and/or deeper muscle contractions. Extended pulse widths or extended durations of the stimulation train can deliver stimulation over longer periods of time to extend the duration of the muscle contractions. In the case of diaphragm muscle stimulation, longer pulse widths have the potential to help expand the lower lung lobes by providing greater or extended negative pressure around the outside of the lungs. Such negative pressure has the potential to help prevent or mitigate a form of low pressure lung injury known as atelectasis. The increased stimulation of the one or more phrenic nerves 26, 28 may result in a more forceful contraction of the diaphragm 30, causing the patient to inhale a greater volume of air, thereby providing a greater amount of oxygen to the patient. Sigh breaths may increase patient comfort.

In other examples, buttons 17, 19 may allow the patient or other user to start and stop stimulation therapy, or to increase or decrease stimulation parameters, including stimulation charge (amplitude×pulse width), frequency of pulses in a stimulation train, or breath rate. LED indicators or a small LCD screen (not shown) on the controller may provide other information to guide or inform the operator regarding the stimulation parameters, the feedback from the system sensors, or the condition of the patient.

FIG. 3 illustrates another example of system 10 in which a control unit 14″ is implanted in the patient, along with catheter 12. System 10 may further include remote controller 16 and a programmer 98 that communicates with control unit 14″ wirelessly. In this embodiment, each of programmer 98, control unit 14″, and remote controller 16 may include a wireless transceiver 92, 94, 96, respectively, so that each of the three components can communicate wirelessly with each other. Control unit 14″ may include all of the electronics, software, and functioning logic necessary to perform the functions described herein. Implanting control unit 14″ as shown in FIG. 3 may allow catheter 12 to function as a permanent breathing pacemaker. Programmer 98 may allow the patient or health professional to modify or otherwise program the nerve stimulation or sensing parameters. Remote controller 16 may be used as described in connection with FIGS. 1 and 2. In other examples, remote controller 16 may be in the form of a smartphone, tablet, watch or other wearable device.

Catheter Features

Referring to FIGS. 1-3, catheter 12 may include a stimulation array comprising a plurality of electrodes 34 or other energy delivery elements. In one example, electrodes 34 may be surface electrodes located on an outer wall of catheter 12. In another example, electrodes 34 may be positioned radially inward relative to the outer wall of catheter 12 (e.g., exposed through openings in the outer wall). In yet another example, the electrodes 34 may include printed electrodes as described in U.S. Pat. No. 9,242,088, which is incorporated by reference herein (see below).

Electrodes 34 may extend partially around the circumference of catheter 12. This “partial” electrode configuration may allow electrodes 34 to target a desired nerve for stimulation, while minimizing application of electrical charge to undesired areas of the patient's anatomy (e.g., other nerves or the heart). As shown in FIG. 1, catheter 12 may include a proximal set 35 of electrodes 34 configured to be positioned proximate to and stimulate left phrenic nerve 26 and a distal set 37 of electrodes 34 configured to be positioned proximate to and stimulate right phrenic nerve 28. As shown in FIG. 5, electrodes 34 may be arranged in rows extending along the length of catheter 12. In one example, proximal set 35 may include two rows, and distal set 37 may include two rows.

Furthermore, the catheters described herein may include any features of the nerve stimulation devices described in the following documents, which are all incorporated by reference herein in their entireties: U.S. Pat. No. 8,571,662 (titled “Transvascular Nerve Stimulation Apparatus and Methods,” issued Oct. 29, 2013); U.S. Pat. No. 9,242,088 (titled “Apparatus and Methods for Assisted Breathing by Transvascular Nerve Stimulation,” issued Jan. 26, 2016); U.S. Pat. No. 9,333,363 (titled “Systems and Related Methods for Optimization of Multi-Electrode Nerve Pacing,” issued May 10, 2016); U.S. application Ser. No. 14/383,285 (titled “Transvascular Nerve Stimulation Apparatus and Methods,” filed Sep. 5, 2014); or U.S. application Ser. No. 14/410,022 (titled “Transvascular Diaphragm Pacing Systems and Methods of Use,” filed Dec. 19, 2014). In addition, the control units described herein can have any of the functionality of the control units described in the above-referenced patent documents (e.g., the control units described herein can implement the methods of nerve stimulation described in the incorporated documents).

During nerve stimulation, one or more electrodes 34 may be selected from the proximal set 35 for stimulation of left phrenic nerve 26, and one or more electrodes 34 may be selected from the distal set 37 for stimulation of right phrenic nerve 28. Catheter 12 may stimulate nerves using monopolar, bipolar, or tripolar electrode combinations, or using any other suitable combination of electrodes 34. In some examples, a second or third stimulation array can be used to stimulate other respiratory muscles. When multiple nerves or muscles are being stimulated, the controller and sensors described herein may be used to coordinate stimulation to achieve the desired muscle activation, breath, or level of respiratory support.

Catheter 12 may further include one or more lumens. Each lumen may extend from a proximal end of catheter 12 to a distal end of catheter 12, or to a location proximate the distal end of catheter 12. The lumens may contain medical devices, such as a guidewire or an optical fiber camera. Furthermore, the one or more lumens may be used for any suitable purpose, such as drawing blood samples or providing a pathway for delivering medications into the patient. In some examples, lumens may contain or be fluidly connected to sensors, such as blood gas sensors or pressure sensors.

In this disclosure, the figures illustrating catheter 12 may each illustrate different features and different combinations of features. However, catheter 12 may include any combination of the features that are described herein. Accordingly, the features of catheter 12 are not limited to the specific combinations shown in the various figures.

Referring to FIG. 2, a hub 36 may be connected to the proximal end of catheter 12. Hub 36 may include a conductive surface and can act as a reference electrode during monopolar stimulation or sensing. In some embodiments, hub 36 may be sutured on a patient's skin. In addition, hub 36 may be used as an ECG electrode.

FIG. 4 illustrates catheter 12 inserted into left jugular vein 32 and superior vena cava 24. As described above, catheter 12 includes a plurality of electrodes 34, with proximal electrodes 34 positioned near left phrenic nerve 26 and distal electrodes 34 positioned near right phrenic nerve 28. Catheter 12 may further include three lumens (not shown) that connect with extension lumens 38, 40, 42 that extend proximally from hub 36. The distal portion of catheter 12 may be configured to assume a helical shape 44 when positioned within the patient. Helical shape 44 may help anchor catheter 12 to the vessel wall to stabilize catheter 12 during nerve stimulation. Furthermore, helical shape 44 may allow electrodes 34 to be positioned at different radial positions within the vessel, which may be useful when selecting electrodes for nerve stimulation. For example, in certain instances it may be desirable to stimulate the nerve with electrodes 34 that are closer to the nerve (e.g., to obtain a stronger diaphragm response), and in other instances it may be desirable to stimulate the nerve with electrodes 34 that are farther away from the nerve (e.g., to obtain a weaker diaphragm response, or prevent stimulation of the vagus nerve).

In one example, helical shape 44 may be obtained by using a stiffening wire inserted into a lumen of catheter 12 via an extension lumen 38, 40, or 42. The stiffening wire may include a shape-memory material (e.g., Nitinol) biased to a helical shape, stainless steel, or any other suitable material. The portion of catheter 12 configured to assume the helical shape 44 may include materials having a lower stiffness than other portions of catheter 12. For example, the materials along helical shape 44 may be thinner or more flexible than the materials along the remaining length of catheter 12. In another example, catheter 12 may include a temperature-activated shape memory material (e.g., Nitinol) along a portion of its length, such that the shape-memory material of catheter 12 may have a substantially straight shape at room temperature and may assume a helical shape when heated within the patient's body.

In some examples, the proximal portion of catheter 12 additionally or alternatively may have a feature, similar to the distal portion of catheter 12, to allow it to assume a helical shape when positioned within left jugular vein 32 (or left subclavian vein 22). Any proximal helical shape may be obtained or result from any of the features described in connection with helical shape 44. If both the proximal and distal portions of catheter 12 assume a helical shape when positioned within the patient, both the proximal and distal electrodes 34 may be fixed relative to the left and right phrenic nerves 26, 28, respectively. To account for body movements when the patient breathes or moves, catheter 12 may further include a helical shape along a central portion of catheter 12. In one example, the diameter of an expanded helical shape in the central portion may be less than the diameter of the vessel wall, so that the central helical shape is not fixed relative to the vessel wall. Accordingly, the central helical portion may allow catheter 12 to freely expand and contract in length within the vessel as body movements cause the distance between the proximal helix and the distal helix (which may be fixed relative to the vessel walls) to vary. The central helical shape may be obtained or result from any of the features described in connection with helical shape 44.

Referring to FIG. 5, each of the extension lumens 38, 40, and 42 may end in a proximal-most port 38a, 40a, and 42a, respectively. Further, the lumens internal to catheter 12 may terminate in one or more distal ports. In one example, internal lumens that communicate with lumens 38, 40, and 42 terminate at a distal port 48, medial port 50, and proximal port 52, respectively. Lumens 38, 40, 42 and their corresponding internal lumens may be used to transport fluid to and from the patient, such as to deliver medications or withdraw blood or other bodily fluids. In other examples, these lumens may be used to hold a guidewire, stiffening wire, optical fiber camera, sensors, or other medical devices. FIG. 5 illustrates an optical fiber camera 46 inserted into lumen 38, extending through a corresponding internal lumen, and exiting from distal port 48.

FIG. 6 illustrates another example of catheter 12. Catheter 12 is similar to the catheter of FIG. 5, except electrodes 34 may be formed by conductive inks (such as silver, gold, graphine, or carbon flakes suspended in polymer or other media) printed on the surface of catheter 12, as described in U.S. Pat. No. 9,242,088, incorporated by reference herein (see above). These conductive inks may be deposited and adhered directly onto catheter 12 and sealed, except for the exposed electrodes 34, with an outer polyurethane or other flexible insulative film. The exposed electrodes 34 may be coated (e.g., with titanium nitride) for purposes such as one or more of: enhancing electrical properties, such as conductivity and surface area; providing corrosion resistance; and reducing the potential for formation of silver oxide, which could be toxic. As can be seen in FIG. 6, the conductive ink trace of distal electrodes may travel proximally along catheter 12 past the more proximal electrodes 34. FIG. 6 further illustrates catheter 12 having an ultrasound transducer 54 at a distal end of catheter 12, which will be described further below.

Detailed System Components

FIG. 7 illustrates a block diagram of the various components of system 10. The electrodes 34a-34j, hub 36, and lumens 38, 40, 42, 58, and 60 may be part of catheter 12 described herein. Catheter 12 may have any number of electrodes and any number of lumens. Five lumens are illustrated in FIG. 7, but in different examples, the catheter may include one, two, three, four, or more than five lumens. In one example, catheter 12 may have three lumens (e.g., extension lumens 38, 40, 42 and corresponding internal lumens), which each may hold one or more of a guidewire or optical fiber camera, or may be used for fluid delivery or blood sample extraction (box 43). In another example, catheter 12 may include four lumens, with one lumen 58 holding or fluidly connected to a pressure sensor 90, one lumen 60 holding or fluidly connected to a blood gas sensor 62, and the other two lumens holding a guidewire or optical fiber camera and/or being used for fluid delivery or blood sample extraction. It should be understood that any lumen of system 10 may contain or be fluidly connected to any of the devices (e.g., sensors, guidewire, optical fiber camera) described herein and/or may be used for any of the functions described herein (e.g., fluid delivery, blood sample extraction).

System 10 may include a controller 64, which may be part of any of the control units described herein. Each of the components of system 10 may be operably coupled to the controller 64, and controller 64 may manage operation of electrodes 34 during nerve stimulation, control the gathering of information by various sensors and electrodes 34, and control fluid delivery or extraction. It should be understood that the various modules described herein may be part of a computing system and are separated in FIG. 7 for explanatory purposes only; it is not necessary for the modules to be physically separate.

Electrodes 34a-34j may be electronically coupled to switching electronics 56, which may be communicably coupled to controller 64. As shown in FIG. 7, a portion of electrodes 34 may be distal electrodes 34a-34d, and a portion of electrodes 34 may be proximal electrodes 34g-34j. Other electrodes 34, such as electrodes 34e and 34f, may be positioned between the proximal and distal electrodes and, depending on the placement of catheter 12, may be used for stimulating either left or right phrenic nerves 26, 28. Hub 36 also may be connected to switching electronics 56 and may be used as an electrode.

Electrodes 34a-34j may be used for both electrically stimulating nerves and for gathering physiological information. When being used for nerve stimulation, a first combination of electrodes (e.g., one, two, three, or more electrodes) may be electrically coupled to a first stimulation module channel 70 for stimulation of a first nerve (e.g., the right phrenic nerve) and a second combination of electrodes (e.g., one, two, three, or more electrodes) may be electrically coupled to a second stimulation module channel 72 for stimulation of a second nerve (e.g., the left phrenic nerve). Electrical signals may be sent from the first and second stimulation module channels 70, 72 to the electrode combinations to cause the electrodes to stimulate the nerves. In other examples, more than two electrode combinations (e.g., 3, 4, or more) may be used to stimulate one or more target nerves, and system 10 may include more than two stimulation module channels.

Electrodes 34a-34f may be further configured to sense physiological information from a patient, such as nerve activity, ECG, or electrical impedance, as will be described further below. When being used for sensing, one or more of electrodes 34a-34f may be electronically coupled to a signal acquisition module 68. Signal acquisition module 68 may receive signals from electrodes 34.

Switching electronics 56 may selectively couple electrodes 34 to first stimulation module channel 70, second stimulation module channel 72, or signal acquisition module 68. For example, if an electrode 34 (e.g., electrode 34a) is being used to acquire a signal, such as an ECG signal, that electrode 34 may be coupled via switching electronics 56 to signal acquisition module 68. Similarly, if a pair of electrodes (e.g., electrodes 34b and 34d) is being used to stimulate right phrenic nerve 28, those electrodes may be coupled via switching electronics 56 to first stimulation module channel 70. Finally, if a pair of electrodes (e.g., electrodes 34g and 34h) is being used to stimulate left phrenic nerve 26, those electrodes may be coupled via switching electronics 56 to second stimulation module channel 72. Switching electronics 56 may change which electrodes 34 are used for stimulation and which are used for sensing at any given time. In one example, any electrode 34 can be used for nerve stimulation and any electrode 34 can be used for sensing functions described herein. In other words, each electrode 34 may be configured to stimulate nerves, and each electrode 34 may be configured to sense physiological information.

Signal acquisition module 68 may further be coupled to one or more sensors configured to gather physiological information from a patient. For example, system 10 may include one or more of blood gas sensor 62 or pressure sensor 90. These sensors may be located in lumens of catheter 12, outside of the patient in fluid communication with a lumen, on an outer surface of catheter 12, or in any other suitable location. In one example, blood gas sensor 62 may be housed in or fluidly connected to lumen 60, while pressure sensor 90 may be housed in or fluidly connected to lumen 58. Blood gas sensor 62 may measure the amount of O2 or CO2 in the patient's blood. Pressure sensor 90 may measure the central venous pressure (CVP) of the patient.

Signal acquisition module 68 may transmit the signals received from one or more of electrodes 34, blood gas sensor 62, and/or pressure sensor 90 to the appropriate processing/filtering module of system 10. For example, signals from pressure sensor 90 may be transmitted to a central venous pressure signal processing/filtering module 84, where the signals are processed and filtered to aid in interpretation of CVP information. Similarly, signals from blood gas sensor 62 may be transmitted to a blood gas signal processing/filtering module 86 for processing and filtering to determine blood gas levels. Signals from electrodes 34, when they are used for sensing, may be sent to nerve signal processing/filtering module 80, ECG signal processing/filtering module 82, or impedance signal processing/filtering module 88, as appropriate. Signals from electrodes 34 or other sensors may be sent to amplification module 78, if necessary, to amplify the signals prior to being sent to the appropriate processing/filtering module.

Controller 64 may further communicate with display 74, which may serve as a user interface and may have a touch screen 18 (see FIG. 1). System 10 may further include software/firmware 76, which may contain the instructions necessary for carrying out the various functions described herein. Finally, system 10 may include data storage 79, for storing information gathered during sensing operations of catheter 12, and/or for storing instructions related to the operation of any of the modules or instructions for carrying out any of the functions described herein. Catheter 12 may contain unique identification features (e.g., RFID), and in the event the system 10 described herein (e.g., having one or more of controllers/programmers 14, 14′, 14″, 98, 64) is used to treat multiple patients concurrently, the catheter identification feature may allow the system 10 to uniquely identify each patient and access that patient's stored patient data.

Catheter Positioning

Catheter 12 may include a variety of positioning features that may help a user to position catheter 12 within a patient. Some positioning features may be visualization aids, such as optical fiber camera 46 shown in FIG. 5 or ultrasound transducer 54 shown in FIG. 6. Other positioning features may be sensors to sense physiological parameters, such as pressure sensor 90. Electrodes 34, which can be used to stimulate a nerve, also may be used as sensors to gather information that can then be used to position catheter 12. For example, electrodes 34 may gather information related to nerve activity (e.g., the left or right phrenic nerve), ECG signals, and/or impedance. Accordingly, a sensing electrode 34 may be considered a positioning feature. Each of the positioning features and how they are used to help position catheter 12 will be described in further detail below.

Catheter 12 may include any combination of positioning features, including one or more visualization aids, sensors (e.g., pressure), or electrodes capable of sensing various types of information. Similarly, the control units described herein, whether on a cart, wearable on a patient, or wireless, may be configured to process information gathered by the various positioning features described herein (e.g., visualization aids, sensors, and electrodes), as well as perform the various computerized functions described herein.

Referring back to FIG. 5, optical fiber camera 46 may be positioned within extension lumen 38 and its corresponding internal lumen within catheter 12, either temporarily or as an integral, permanent component of catheter 12. It should be understood that optical fiber camera 46 could be inserted into any of the extension lumens 38, 40, 42 and internal lumens, and could exit any of the ports 48, 50, 52. Optical fiber camera 46 may be used to aid in positioning of catheter 12 within the patient. For example, images from optical fiber camera 46 may be transmitted in real time to a health professional or other user during a procedure, who may rely on the images to guide catheter 12 through the patient's vessels and/or to adjust the position of the catheter within the vessels.

Referring back to FIG. 6, ultrasound transducer 54 may be used in addition to or instead of optical fiber camera 46 to obtain information useful for positioning catheter 12 within the patient. Ultrasound transducer 54 may be secured temporarily or permanently to the exterior of catheter 12, as shown in FIG. 6, or may be positioned temporarily or permanently within a lumen of catheter 12 (e.g., positioned to extend from the distal end of a lumen of catheter 12). Positioning ultrasound transducer 54 near the distal tip of catheter 12 may allow the user to view the inside of vessels and also ensure that the tip of catheter 12 is not positioned in an undesired location (e.g., in the atrium of the heart). For example, ultrasound transducer 54 may allow visualization of a heart valve, which could indicate that the catheter 12 has entered the atrium and may need to be retracted.

In addition to allowing a user to see the inside of the patient's vessels, the ultrasound images may provide information (e.g., calculated or visual) about the diameter of blood vessels and/or blood flow within the vessels. The user may then use vessel diameter information, blood flow, and real time images of the inside of the patient's vessels to position catheter 12 in a desired position.

CVP measurements from pressure sensor 90 may further aid in positioning catheter 12 within the patient. Normal values may vary between 4-12 cmH2O. The CVP waveform may change based on the location, relative to the patient's heart, of the port (e.g., 46, 48, or 50) in communication with pressure sensor 90. In one example, CVP measurements may decline as the relevant port approaches the patient's heart. A user may read the changing CVP waveforms to help position the catheter 12 in a desired location relative to the patient's heart.

The CVP waveform has several components. The (a) wave corresponds to the right atrial contraction and correlates with the P wave on the ECG. The (c) wave corresponds to the cusp of the tricuspid valve protruding backwards through the atrium, as the right ventricle begins to contract. The (c) wave correlates with the end of the QRS complex on the ECG. The (x) descent corresponds to the movement of the right ventricle, which descends as it contracts. The downward movement decreases the pressure in the right atrium. At this stage, there is also atrial diastolic relaxation, which further decreases the right atrial pressure. The (x) descent happens before the T wave on the ECG. The (v) wave occurs as blood fills the right atrium and hits the tricuspid valve, causing a back-pressure wave. The (v) wave occurs after the T wave of the ECG. The (y) descent is a pressure decrease caused by the tricuspid valve opening in early ventricular diastole and occurs before the P wave of the ECG. The amplitudes of a, c, x, v, y may change depending on the position of the catheter with respect to the heart. The signature change of the CVP waveform can guide in the placement of catheter 12.

In one example, a method for positioning intravascular catheter 12 may include positioning catheter 12 in a first position in a venous system of a patient, wherein catheter 12 includes a plurality of electrodes 34 and at least one lumen extending from a proximal end of catheter 12 to a distal end of catheter 12, and each electrode 34 of the plurality of electrodes 34 is configured to emit electrical signals to stimulate a nerve; measuring a central venous pressure of the patient using a pressure sensor 90 fluidly connected to the at least one lumen; and based on the central venous pressure, adjusting catheter 12 to a second position different from the first position.

Nerve signals acquired by electrodes 34 also may be used to aid in positioning catheter 12 within a patient. The electrical signal from a nerve may be amplified by amplification module 78 and processed by nerve signal processing/filtering module 80. The amplified and filtered signals from one or more electrodes 34 then may be compared to an expected signal from the targeted nerve (e.g., left or right phrenic nerve) to identify electrodes 34 in close proximity to the target nerve and to identify the optimal one or more electrodes for nerve stimulation. For example, electrodes 34 returning a higher strength and/or higher quality signal may be located closer to the target nerve.

More specifically, phrenic nerve activity can be recorded using bipolar or monopolar electrodes. Phrenic nerve discharge can be amplified and filtered (e.g., 100 Hz to 5 kHz), and a moving average can be obtained using a third-order Paynter filter with a 20 or 50 ms time constant. Phrenic nerve discharge also can be filtered at 10 Hz to 5 kHz for analysis of spectral composition. A sampling rate of 1-10 kHz can be used to capture the nerve activity.

The parameters acquired during nerve activity sensing can be used to detect if the signal is from the phrenic nerve or another nerve. Sensed parameters can include a number of physiological parameters, such as amplitude, inspiration duration, and/or breathing rate. For example, if the sensed amplitude shows proximity of the electrodes 34 to the nerve and the nerve is a phrenic nerve, the duration of pulses in a train should match the sensed inspiration duration, and the frequency of the trains should match the sensed breathing rate. Furthermore, the sensed signals from a nerve can be compared to known nerve signatures (e.g., of phrenic nerves) to confirm that the nerve signal is from the desired nerve.

Electrodes 34 (e.g., two or three) may be used to acquire ECG signals, with hub 36 optionally being used as a reference electrode. The ECG signal (e.g., morphology, amplitudes, and spectral content) may vary depending on the location, relative to the patient's heart, of the electrodes being used to measure the signal. Monitoring changes in the ECG signal as catheter 12 is being positioned may aid in identifying desired or undesired placement. For example, it may be undesired for catheter 12 to be placed in the atrium of the patient's heart.

In one example, one of the distal electrodes 34 on catheter 12 may be designated as a probe. Other electrodes along the length of catheter 12, and in some cases in contact with the skin of the patient, may be used to detect an ECG signal, which can optionally be displayed by control unit 14 via screen 18. Catheter 12 may be advanced through superior vena cava 24 towards the heart. As catheter 12 enters a region proximate the right atrium, or enters the right atrium, the P-wave portion of the ECG may become elevated and create an augmented peaked P-wave, indicating that the tip of the catheter 12 lies in or very close to the right atrium. The operator can observe the change in P-wave, or the control unit 14 can utilize an algorithm to detect the change and provide a visual, audible or other signal to the operator. For example, an LED on catheter hub 36, control unit 14, or remote controller 16 can change from green to yellow and then to red as the P-wave changes indicate that the catheter 12 is approaching and then is positioned within the right atrium. The catheter 12 can then be withdrawn slowly until the P-wave starts to diminish. The catheter 12 can then be withdrawn a further 1-2 cm, thereby positioning the catheter tip in the distal portion of superior vena cava 24.

In this example, the positive deflection in the P-wave occurs when current flows to the probing electrode, and a negative deflection when it flows away. The P-wave depolarizes down the right atrium from the SA node, away from an electrode 34 in superior vena cava 24, and is therefore negative. The amplitude of the P-wave is related to the inverse square rule, whereby the amplitude is inversely proportional to the square of the distance from the current source. Thus, the P-wave increases greatly in negative amplitude as catheter 12 approaches the atrium. When the tip enters the atrium, it is just beyond the SA node, and the first portion of the P-wave depolarizes towards it. This results in a brief, small positive deflection followed instantly by a deep negative deflection.

Alternatively, a distal combination of electrodes 34 (e.g., a distal pair) and a proximal combinations of electrodes 34 (e.g., a proximal pair) can be used to obtain, respectively, a distal and proximal ECG signal having a P-wave. The P-waves can be compared using standard signal processing techniques and a delta value can be determined as the catheter 12 is advanced through the vessel (e.g. superior vena cava 24) towards the heart. As catheter 12 is advanced in close proximity to or into the atrium, the delta value will change significantly, exceeding a predetermined value. The system 10 can provide an indicator to the operator, as described previously, and catheter 12 can be withdrawn 1 to 2 cm. This method can also utilize one or more reference electrodes 34 located along the length of the catheter or positioned externally on the patient's body.

Electrodes 34 also may be used to measure impedance, which can provide information relevant to positioning catheter 12. Impedance may be measured between any two electrodes 34 of catheter 12. In one example, however, impedance may be measured between: a) either a proximal-most electrode 34 or hub 36, and b) a distal-most electrode.

The impedance presented to injected current may be dependent on the conductivity of the fluid, or adjacent tissue, in the local area between a pair of sensing electrodes 34. The conductivity further may depend on the cross-sectional area of the blood vessel at the site of the sending electrodes 34. The impedance of an electrode 34 may vary depending on the medium in which it is resting. For example, an electrode 34 placed in a relatively large body of conductive fluid may have a lower impedance than one resting against a vessel wall. The impedance of an electrode 34 can therefore be used to determine whether it is adjacent to a vessel wall or resting in a larger body of conductive fluid.

In one example, when catheter 12 is inserted into a patient, electrodes 34 that are on a proximal portion of catheter 12 may have a higher impedance than other electrodes 34, because the proximal portion of catheter 12 may be positioned in tissue (e.g., fatty) near an insertion site, rather than resting in the fluid of a blood vessel. Electrodes 34 farther down the shaft of catheter 12, towards a central portion of catheter 12, might have progressively lower impedances as the diameter of the vessel increases (e.g., as the vessel approaches superior vena cava 24). Electrodes 34 on the portion of catheter 12 that is floating in fluid in superior vena cava 24 might have a low impedance. Electrodes 34 on the distal portion of catheter 12, at or near the tip of catheter 12, might be in direct contact with the vessel wall and therefore may have a higher impedance. A graph of the impedances of all of the electrodes 34 in this example may have a U-shaped curvature, as impedances may be higher at each end of catheter 12 and lower towards the central portion of catheter 12. The change in impedance of an electrode 34 as it progresses through the patient's vessels can provide information about the location of that electrode 34. In addition, the differences in impedances of electrodes 34 along the length of catheter 12 may provide information about the placement of catheter 12.

In one example, catheter 12 may be placed in a vessel that varies in diameter, with distal electrodes 34 resting in a desired vessel (e.g., in superior vena cava 24). The impedances of different, more proximal electrodes would be expected to vary depending on their position in the venous system. In one example, catheter 12, when placed in a desired position, would be expected to include: 1) electrodes 34 whose impedances are reduced as the electrodes 34 approach the wall of a vessel (e.g., superior vena cava 24); and 2) electrodes 34 having impedance profiles with a desired shape. In one example, measured impedances may be compared to impedance thresholds or profiles stored in data storage 79, to determine if one or more electrodes 34 are properly placed.

In another example, the impedances of distal electrodes can be compared to the impedances of proximal electrodes as the catheter 12 is advanced through superior vena cava 24 towards the atrium. As the distal electrodes enter the atrium, the difference between the distal and proximal impedance measurements may exceed a predetermined threshold allowing the system 10 to provide an indication to the operator. Catheter 12 can then be withdrawn (or advanced depending on the application) to the desired location. Signal filtering, processing, and analytical techniques known in the art can be used to assess the impedance measurements in real time.

A catheter 12 that is under-inserted may have few or no electrodes 34 resting in the desired vessel (e.g., superior vena cava 24), which would result in electrode impedance profiles having different shapes than the desired shape. In addition, a catheter 12 that is over-inserted may have one or more electrodes 34 that are close to, or in contact with, the atrium, which may also result in impedance profiles having different shapes than the desired shape. In one example, the impedance of one or more electrodes 34 is monitored as catheter 12 is inserted into the patient and electrodes 34 move through the patient's venous system. Changes in the impedance profiles can be displayed to the health professional performing the insertion, and the impedance profiles can be used to confirm proper placement of catheter 12.

In one example, a method for positioning intravascular catheter 12 may include positioning catheter 12 in a first position in a venous system of a patient, wherein catheter 12 includes a plurality of electrodes 34, and each electrode 34 of the plurality of electrodes 34 is configured to emit electrical signals to stimulate a phrenic nerve; measuring an impedance between a first electrode 34 of the plurality of electrodes 34 and a second electrode; and based on the measured impedance, adjusting catheter 12 to a second position different from the first position.

In other examples, catheter 12 may include a strain gauge and/or an accelerometer (not shown). Either the strain gauge or the accelerometer may be placed at or near the distal end of catheter 12, in one of the lumens. The strain gauge could detect flex in a distal portion of catheter 12, and the accelerometer could detect movement/acceleration of the distal portion of catheter 12. Information from the strain gauge and/or accelerometer could be used to determine whether the distal end of catheter 12 is in the atrium (e.g., heartbeats may cause movement of the distal end of catheter 12). The strain gauge or the accelerometer could be an integral, permanent part of catheter 12 or could be positioned in a lumen of catheter 12 temporarily during positioning of catheter 12.

Electrode Selection and Determining Stimulation Parameters

Nerve signals acquired by sensing electrodes 34 may be used to select electrodes 34 for nerve stimulation. Electrodes 34 that are closer to a target nerve may sense nerve activity having a higher amplitude, while electrodes 34 that are farther from a target nerve may sense nerve activity having a lower amplitude. If a greater diaphragm response is desired, electrodes 34 that are closer to the nerve, as determined based on received nerve activity signals, may be selected for nerve stimulation. In other cases, if less diaphragm response is desired, electrodes 34 that are farther from the nerve, as determined based on received nerve activity signals, may be selected for nerve stimulation.

Typical nerve signals for, e.g., phrenic nerves, follow a pattern that has distinct characteristics (e.g., spectral characteristics and modulation over time). To select electrodes 34 for nerve stimulation, the sensed nerve signals from different electrodes 34 can be analyzed for their spectral and temporal characteristics. Of electrodes 34 having sensed signal patterns matching typical phrenic nerve activity, the optimal electrodes 34 can be selected based on the amplitude of the signal and how strongly the signal correlates to the typical pattern. In one example, a fast Fourier transform can be used to provide a correlation factor to a reference signal in near real-time. In another example, the sensed signals can be frequency filtered in the frequency range of interest, based on the typical characteristics of the phrenic nerve signal, and then analyzed over time to observe periods or bursts of activity in the frequency range of interest.

In one example, a method for selecting one or more electrodes for nerve stimulation may include inserting intravascular catheter 12 into: a) at least one of left subclavian vein 22 or left jugular vein 32, and b) superior vena cava 24, wherein catheter 12 includes a plurality of electrodes 34, and each electrode 34 of the plurality of electrodes 34 is configured to emit electrical signals to stimulate a nerve; using one or more electrodes 34 of the plurality of electrodes 34 to acquire an electrical signal emitted from the nerve; based on the acquired electrical signal, selecting an electrode 34 or an electrode combination for a nerve stimulation; and using the selected electrode 34 or electrode combination, stimulating the nerve.

The processed nerve activity waveforms additionally may be used to determine parameters for nerve stimulation. The processed waveforms may provide information regarding intrinsic breath rate (e.g., if the patient is attempting to breathe on his/her own) and nerve signal amplitude. The stimulation parameters may be adjusted based on the breath rate of previous stimulated breaths (e.g., to increase or decrease the breath rate, as sensed by the sensing electrodes) and nerve activity resulting from stimulation during previous breaths (e.g., to increase or decrease the strength of stimulation). Various parameters that may be adjusted include stimulation pulse amplitude, stimulation pulse width, stimulation pulse frequency, stimulation duration, and the interval between stimulations/pulse trains (e.g., stimulated breath rate). Accordingly, sensed nerve activity signals may be used to determine and adjust the nerve stimulation parameters in a closed-loop system.

Impedance information may be used to determine a breath rate of the patient in order to adjust nerve stimulation parameters (e.g., stimulation pulse amplitude, stimulation pulse width, stimulation pulse frequency, stimulation duration, and the interval between stimulations/pulse trains (e.g., stimulated breath rate)). Electrical impedance of lung tissue changes as a function of air content. Accordingly, the electrical impedance of the thorax changes during inhalation and exhalation. The thorax presents an electrical impedance that includes two components: a relatively constant value and a varying value. Changes in impedance may result from the following two effects during inspiration: 1) there is an increase in the gas volume of the chest in relation to the fluid volume, which may cause conductivity to decrease, and 2) the length of the conductance path (e.g., between two electrodes) increases when the lungs expand. These effects may cause impedance to increase during inspiration. There is an approximately linear correlation between the impedance changes and the volume of respirated air. The varying component of impedance (i.e., respirative impedance) generates a varying voltage component when current is injected (e.g., by electrodes 34). This varying voltage component can then be used to determine the person's breathing rate.

Information from blood gas sensor 62 may be used by a health professional, or by controller 64, to adjust stimulation parameters. For example, if blood O2 levels are low (or blood CO2 levels are high) controller 64 may send a signal to electrodes 34 to emit stimulation signals having a higher charge (amplitude×pulse width) or frequency, and may stimulate a sigh breath. Conversely, if blood O2 levels are high (or blood CO2 levels are low), controller 64 may cause electrodes 34 to emit stimulation signals having a lower charge or frequency. Based on information from blood gas sensor 62, the following parameters can be adjusted: stimulation pulse amplitude, stimulation pulse width, stimulation pulse frequency, stimulation duration, and the interval between stimulations/pulse trains (e.g., stimulated breath rate).

For any of the parameter adjustments described herein, increasing stimulation pulse amplitude, width and/or frequency may increase lung volume during a stimulated breath. Increasing stimulation duration may increase lung volume and/or increase the amount of time air remains in the lungs during a stimulated breath, allowing for an extended gas exchange period. Increasing the stimulated breath rate may allow for additional gas exchange periods over a given period of time, which may increase the amount and/or speed of gas exchange.

The system 10 and catheter 12 described herein may include any combination of sensing features. For example, catheter 12 may be configured to sense ECG, impedance, nerve activity, blood gas levels, and CVP, and the system 10 may be configured to position catheter 12, select electrodes 34 for stimulation, and select stimulation parameters based on one or more types of information received by sensors or electrodes 34.

Accordingly, the various visualization and sensing functions of system 10 may assist a user in one or more of positioning a transvascular catheter, selecting optimal electrodes for nerve stimulation, or selecting or adjusting parameters for nerve stimulation.

While principles of the present disclosure are described herein with reference to illustrative embodiments for particular applications, it should be understood that the disclosure is not limited thereto. Those having ordinary skill in the art and access to the teachings provided herein will recognize additional modifications, applications, embodiments, and substitution of equivalents all fall within the scope of the embodiments described herein. Accordingly, the invention is not to be considered as limited by the foregoing description.

Claims

1. A method, comprising:

inserting a catheter into a first blood vessel and a superior vena cava, wherein the catheter includes a plurality of electrodes;
using one or more electrodes of the plurality of electrodes to acquire one or more electrical signals emitted from a nerve;
based on the one or more electrical signals, positioning the catheter relative to the nerve and selecting at least one electrode to stimulate the nerve; and
stimulating the nerve to cause a contraction of a respiratory muscle.

2. The method of claim 1, further comprising determining whether the one or more electrical signals are from a phrenic nerve.

3. The method of claim 1, further comprising comparing the one or more electrical signals to an expected signal from the nerve.

4. The method of claim 1, wherein the at least one electrode selected for nerve stimulation is positioned closer to the nerve than other electrodes of the plurality of electrodes.

5. The method of claim 1, wherein the at least one electrode selected for nerve stimulation senses nerve activity having a higher amplitude than other electrodes of the plurality of electrodes.

6. The method of claim 1, wherein the first vessel is at least one of: a left subclavian, axillary, cephalic, cardiophrenic, brachial, radial, or left jugular vein.

7. The method of claim 1, wherein the nerve is at least one of a left phrenic nerve or a right phrenic nerve.

8. The method of claim 1, wherein each electrode of the plurality of electrodes is configured to both acquire and emit electrical signals.

9. A method, comprising:

inserting a catheter into a first blood vessel and a superior vena cava, wherein the catheter includes a plurality of electrodes, and the plurality of electrodes include proximal electrodes positioned in the first vessel proximate a first nerve and distal electrodes positioned in the superior vena cava proximate a second nerve;
using one or more electrodes of the proximal electrodes to acquire a first electrical signal emitted from the first nerve;
based on the first electrical signal, selecting at least one electrode of the proximal electrodes to stimulate the first nerve;
using one or more electrodes of the distal electrodes to acquire a second electrical signal emitted from the second nerve;
based on the second electrical signal, selecting at least one electrode of the distal electrodes to stimulate the second nerve;
based on at least one of the first or second electrical signals, positioning the catheter relative to the first or second nerve; and
stimulating at least one of the first or second nerves to cause a contraction of a respiratory muscle.

10. The method of claim 9, wherein the first nerve is a left phrenic nerve, and the second nerve is a right phrenic nerve.

11. The method of claim 9, further comprising determining inspiration duration or breathing rate from at least one of the first or second electrical signals.

12. The method of claim 9, wherein the at least one electrode of the proximal electrodes selected to stimulate the first nerve is closer to the first nerve than other electrodes of the proximal electrodes, and the at least one electrode of the distal electrodes selected to stimulate the second nerve is closer to the second nerve than other electrodes of the distal electrodes.

13. The method of claim 9, further comprising determining a correlation factor between the first electrical signal and a reference signal.

14. The method of claim 9, further comprising applying a frequency filter in a desired range to the first electrical signal and analyzing changes in the desired range over time.

15. The method of claim 9, further comprising determining a breath rate from at least one of the first or second electrical signals and adjusting a stimulation parameter based on the breath rate.

16. The method of claim 9, further comprising, after stimulating at least one of the first or second nerves to cause a contraction of the respiratory muscle:

using one or more electrodes of the plurality of electrodes to acquire a third electrical signal emitted from the stimulated first or second nerve, and
adjusting a stimulation parameter based on the third electrical signal.

17. A method, comprising:

inserting a catheter into: a) at least one of a left subclavian vein or left jugular vein, and b) a superior vena cava, wherein the catheter includes a plurality of electrodes, and the plurality of electrodes include proximal electrodes positioned proximate a left phrenic nerve and distal electrodes positioned proximate a right phrenic nerve;
using one or more electrodes of the proximal electrodes to acquire a first electrical signal emitted from the left phrenic nerve;
based on the first electrical signal, selecting at least one electrode of the proximal electrodes to stimulate the left phrenic nerve;
using one or more electrodes of the distal electrodes to acquire a second electrical signal emitted from the right phrenic nerve;
based on the second electrical signal, selecting at least one electrode of the distal electrodes to stimulate the right phrenic nerve;
based on at least one of the first or second electrical signals, positioning the catheter relative to the left or right phrenic nerve; and
stimulating at least one of the left or right phrenic nerves to cause a contraction of a diaphragm.

18. The method of claim 17, wherein each electrode of the plurality of electrodes is configured to both acquire and emit electrical signals.

19. The method of claim 17, further comprising adjusting a stimulation parameter based on at least one of the first or second electrical signals.

20. The method of claim 17, further comprising using one or more electrodes of the plurality of electrodes to sense at least one of an impedance or an ECG signal.

Referenced Cited
U.S. Patent Documents
1693734 December 1928 Waggoner
2532788 December 1950 Sarnoff
2664880 January 1954 Wales, Jr.
3348548 October 1967 Chardack
3470876 October 1969 Barchilon
3769984 November 1973 Muench
3804098 April 1974 Friedman
3817241 June 1974 Grausz
3835864 September 1974 Rasor et al.
3847157 November 1974 Caillouette et al.
3851641 December 1974 Toole et al.
3896373 July 1975 Zelby
3938502 February 17, 1976 Bom
4054881 October 18, 1977 Raab
4072146 February 7, 1978 Howes
4114601 September 19, 1978 Abels
4173228 November 6, 1979 Van Steenwyk et al.
4249539 February 10, 1981 Vilkomerson et al.
4317078 February 23, 1982 Weed et al.
4380237 April 19, 1983 Newbower
4407294 October 4, 1983 Vilkomerson
4416289 November 22, 1983 Bresler
4431005 February 14, 1984 McCormick
4431006 February 14, 1984 Trimmer et al.
4445501 May 1, 1984 Bresler
4586923 May 6, 1986 Gould et al.
4587975 May 13, 1986 Salo et al.
4643201 February 17, 1987 Stokes
4674518 June 23, 1987 Salo
4681117 July 21, 1987 Brodman et al.
4697595 October 6, 1987 Breyer et al.
4706681 November 17, 1987 Breyer et al.
4771788 September 20, 1988 Millar
4819662 April 11, 1989 Heil, Jr. et al.
4827935 May 9, 1989 Geddes et al.
4830008 May 16, 1989 Meer
4840182 June 20, 1989 Carlson
4852580 August 1, 1989 Wood
4860769 August 29, 1989 Fogarty et al.
4905698 March 6, 1990 Strohl, Jr. et al.
4911174 March 27, 1990 Pederson et al.
4934049 June 19, 1990 Kiekhafer et al.
4944088 July 31, 1990 Doan et al.
4951682 August 28, 1990 Petre
4957110 September 18, 1990 Vogel et al.
4989617 February 5, 1991 Memberg et al.
5005587 April 9, 1991 Scott
5042143 August 27, 1991 Holleman et al.
5056519 October 15, 1991 Vince
5115818 May 26, 1992 Holleman et al.
5146918 September 15, 1992 Kallok et al.
5170802 December 15, 1992 Mehra
5184621 February 9, 1993 Vogel et al.
5224491 July 6, 1993 Mehra
5243995 September 14, 1993 Maier
5267569 December 7, 1993 Lienhard
5314463 May 24, 1994 Camps et al.
5316009 May 31, 1994 Yamada
5330522 July 19, 1994 Kreyenhagen
5345936 September 13, 1994 Pomeranz et al.
5383923 January 24, 1995 Webster, Jr.
5411025 May 2, 1995 Webster, Jr.
5417208 May 23, 1995 Winkler
5451206 September 19, 1995 Young
5456254 October 10, 1995 Pietroski et al.
5465717 November 14, 1995 Imran et al.
5476498 December 19, 1995 Ayers
5486159 January 23, 1996 Mahurkar
5507725 April 16, 1996 Savage et al.
5524632 June 11, 1996 Stein et al.
5527358 June 18, 1996 Mehmanesh et al.
5531686 July 2, 1996 Lundquist et al.
5555618 September 17, 1996 Winkler
5567724 October 22, 1996 Kelleher et al.
5584873 December 17, 1996 Shoberg et al.
5604231 February 18, 1997 Smith et al.
5665103 September 9, 1997 Lafontaine et al.
5678535 October 21, 1997 Dimarco
5683370 November 4, 1997 Luther et al.
5709853 January 20, 1998 Iino et al.
5716392 February 10, 1998 Bourgeois et al.
5733255 March 31, 1998 Dinh et al.
5755765 May 26, 1998 Hyde et al.
5776111 July 7, 1998 Tesio
5779732 July 14, 1998 Amundson
5782828 July 21, 1998 Chen et al.
5785706 July 28, 1998 Bednarek
5788681 August 4, 1998 Weaver et al.
5813399 September 29, 1998 Isaza et al.
5814086 September 29, 1998 Hirschberg et al.
RE35924 October 13, 1998 Winkler
5824027 October 20, 1998 Hoffer
5827192 October 27, 1998 Gopakumaran et al.
5944022 August 31, 1999 Nardella et al.
5954761 September 21, 1999 Machek et al.
5967978 October 19, 1999 Littmann et al.
5971933 October 26, 1999 Gopakumaran et al.
5983126 November 9, 1999 Wittkampf
6006134 December 21, 1999 Hill et al.
6096728 August 1, 2000 Collins et al.
6120476 September 19, 2000 Fling et al.
6123699 September 26, 2000 Webster, Jr.
6126649 October 3, 2000 Vantassel et al.
6136021 October 24, 2000 Tockman et al.
6157862 December 5, 2000 Brownlee et al.
6161029 December 12, 2000 Spreigl et al.
6166048 December 26, 2000 Bencherif
6171277 January 9, 2001 Ponzi
6183463 February 6, 2001 Webster, Jr.
6198974 March 6, 2001 Webster, Jr.
6201994 March 13, 2001 Warman et al.
6212435 April 3, 2001 Lattner et al.
6216045 April 10, 2001 Black et al.
6240320 May 29, 2001 Spehr et al.
6251126 June 26, 2001 Ottenhoff et al.
6269269 July 31, 2001 Ottenhoff et al.
6292695 September 18, 2001 Webster, Jr. et al.
6295475 September 25, 2001 Morgan
6360740 March 26, 2002 Ward et al.
6397108 May 28, 2002 Camps et al.
6415183 July 2, 2002 Scheiner et al.
6415187 July 2, 2002 Kuzma et al.
6438427 August 20, 2002 Rexhausen et al.
6445953 September 3, 2002 Bulkes et al.
6449507 September 10, 2002 Hill et al.
6463327 October 8, 2002 Lurie et al.
6508802 January 21, 2003 Rosengart et al.
6526321 February 25, 2003 Spehr
6569114 May 27, 2003 Ponzi et al.
6584362 June 24, 2003 Scheiner et al.
6585718 July 1, 2003 Hayzelden et al.
6602242 August 5, 2003 Fung et al.
6610713 August 26, 2003 Tracey
6630611 October 7, 2003 Malowaniec
6651652 November 25, 2003 Waard
6682526 January 27, 2004 Parker et al.
6702780 March 9, 2004 Gilboa et al.
6718208 April 6, 2004 Hill et al.
6778854 August 17, 2004 Puskas
6844713 January 18, 2005 Steber et al.
6881211 April 19, 2005 Schweikert et al.
6885888 April 26, 2005 Rezai
6907285 June 14, 2005 Denker et al.
6934583 August 23, 2005 Weinberg et al.
6981314 January 3, 2006 Black et al.
6999820 February 14, 2006 Jordan
7018374 March 28, 2006 Schon et al.
7047627 May 23, 2006 Black et al.
7071194 July 4, 2006 Teng
7072720 July 4, 2006 Puskas
7077823 July 18, 2006 McDaniel
7082331 July 25, 2006 Park et al.
7130700 October 31, 2006 Gardeski et al.
7142903 November 28, 2006 Rodriguez et al.
7149585 December 12, 2006 Wessman et al.
7155278 December 26, 2006 King et al.
7168429 January 30, 2007 Matthews et al.
7184829 February 27, 2007 Hill et al.
7206636 April 17, 2007 Turcott
7225016 May 29, 2007 Koh
7225019 May 29, 2007 Jahns et al.
7229429 June 12, 2007 Martin et al.
7231260 June 12, 2007 Wallace et al.
7235070 June 26, 2007 Vanney
7269459 September 11, 2007 Koh
7277757 October 2, 2007 Casavant et al.
7283875 October 16, 2007 Larsson et al.
7340302 March 4, 2008 Falkenberg et al.
7363085 April 22, 2008 Benser et al.
7363086 April 22, 2008 Koh et al.
7416552 August 26, 2008 Paul et al.
7421296 September 2, 2008 Benser et al.
7454244 November 18, 2008 Kassab et al.
7519426 April 14, 2009 Koh et al.
7553305 June 30, 2009 Honebrink et al.
7555349 June 30, 2009 Wessman et al.
7569029 August 4, 2009 Clark et al.
7591265 September 22, 2009 Lee et al.
7593760 September 22, 2009 Rodriguez et al.
7613524 November 3, 2009 Jordan
7636600 December 22, 2009 Koh
7670284 March 2, 2010 Padget et al.
7672728 March 2, 2010 Libbus et al.
7672729 March 2, 2010 Koh et al.
7676275 March 9, 2010 Farazi et al.
7771388 August 10, 2010 Olsen et al.
7783362 August 24, 2010 Whitehurst et al.
7794407 September 14, 2010 Rothenberg et al.
7797050 September 14, 2010 Libbus et al.
7813805 October 12, 2010 Farazi
7819883 October 26, 2010 Westlund et al.
7840270 November 23, 2010 Ignagni et al.
7853302 December 14, 2010 Rodriguez
7869865 January 11, 2011 Govari et al.
7891085 February 22, 2011 Kuzma et al.
7925352 April 12, 2011 Stack et al.
7949409 May 24, 2011 Bly et al.
7962215 June 14, 2011 Ignagni et al.
7970475 June 28, 2011 Tehrani et al.
7972323 July 5, 2011 Bencini et al.
7974693 July 5, 2011 David et al.
7979128 July 12, 2011 Tehrani et al.
8000765 August 16, 2011 Rodriguez et al.
8021327 September 20, 2011 Selkee
8036750 October 11, 2011 Caparso et al.
8052607 November 8, 2011 Byrd
8104470 January 31, 2012 Lee et al.
8116872 February 14, 2012 Tehrani et al.
8121692 February 21, 2012 Haefner et al.
8135471 March 13, 2012 Zhang et al.
8140164 March 20, 2012 Tehrani et al.
8160701 April 17, 2012 Zhao et al.
8160711 April 17, 2012 Tehrani et al.
8195297 June 5, 2012 Penner
8200336 June 12, 2012 Tehrani et al.
8206343 June 26, 2012 Racz
8233987 July 31, 2012 Gelfand et al.
8233993 July 31, 2012 Jordan
8239037 August 7, 2012 Glenn et al.
8244358 August 14, 2012 Tehrani et al.
8244359 August 14, 2012 Gelfand et al.
8244378 August 14, 2012 Bly et al.
8255056 August 28, 2012 Tehrani
8256419 September 4, 2012 Sinderby et al.
8265759 September 11, 2012 Tehrani et al.
8275440 September 25, 2012 Rodriguez et al.
8280513 October 2, 2012 Tehrani et al.
8335567 December 18, 2012 Tehrani et al.
8348941 January 8, 2013 Tehrani
8369954 February 5, 2013 Stack et al.
8388541 March 5, 2013 Messerly et al.
8388546 March 5, 2013 Rothenberg
8391956 March 5, 2013 Zellers et al.
8401640 March 19, 2013 Zhao et al.
8401651 March 19, 2013 Caparso et al.
8406885 March 26, 2013 Ignagni et al.
8412331 April 2, 2013 Tehrani et al.
8412350 April 2, 2013 Bly
8428711 April 23, 2013 Lin et al.
8428726 April 23, 2013 Ignagni et al.
8433412 April 30, 2013 Westlund et al.
8467876 June 18, 2013 Tehrani
8473068 June 25, 2013 Farazi
8478412 July 2, 2013 Ignagni et al.
8478413 July 2, 2013 Karamanoglu et al.
8478426 July 2, 2013 Barker
8483834 July 9, 2013 Lee et al.
8504158 August 6, 2013 Karamanoglu et al.
8504161 August 6, 2013 Kornet et al.
8509901 August 13, 2013 Tehrani
8509902 August 13, 2013 Cho et al.
8509919 August 13, 2013 Yoo et al.
8512256 August 20, 2013 Rothenberg
8522779 September 3, 2013 Lee et al.
8527036 September 3, 2013 Jalde et al.
8560072 October 15, 2013 Caparso et al.
8571662 October 29, 2013 Hoffer
8617228 December 31, 2013 Wittenberger et al.
8620412 December 31, 2013 Griffiths et al.
8620450 December 31, 2013 Tockman et al.
8626292 January 7, 2014 McCabe et al.
8630707 January 14, 2014 Zhao et al.
8676323 March 18, 2014 Ignagni et al.
8696656 April 15, 2014 Abboud et al.
8706223 April 22, 2014 Zhou et al.
8706235 April 22, 2014 Karamanoglu
8706236 April 22, 2014 Ignagni et al.
8718763 May 6, 2014 Zhou et al.
8725259 May 13, 2014 Kornet et al.
8755889 June 17, 2014 Scheiner
8774907 July 8, 2014 Rothenberg
8781578 July 15, 2014 McCabe et al.
8781582 July 15, 2014 Ziegler et al.
8781583 July 15, 2014 Cornelussen et al.
8801693 August 12, 2014 He et al.
8838245 September 16, 2014 Lin et al.
8858455 October 14, 2014 Rothenberg
8897879 November 25, 2014 Karamanoglu et al.
8903509 December 2, 2014 Tockman et al.
8909341 December 9, 2014 Gelfand et al.
8914113 December 16, 2014 Zhang et al.
8918169 December 23, 2014 Kassab et al.
8942824 January 27, 2015 Yoo et al.
9042981 May 26, 2015 Yoo et al.
9125578 September 8, 2015 Grunwald
9242088 January 26, 2016 Thakkar et al.
9333363 May 10, 2016 Hoffer et al.
9345422 May 24, 2016 Rothenberg
9415188 August 16, 2016 He et al.
9532724 January 3, 2017 Grunwald
9615759 April 11, 2017 Hurezan
20010052345 December 20, 2001 Niazi
20020026228 February 28, 2002 Schauerte
20020065544 May 30, 2002 Smits et al.
20020087156 July 4, 2002 Maguire et al.
20020128546 September 12, 2002 Silver
20020188325 December 12, 2002 Hill et al.
20030078623 April 24, 2003 Weinberg et al.
20030195571 October 16, 2003 Burnes et al.
20040003813 January 8, 2004 Banner et al.
20040010303 January 15, 2004 Bolea et al.
20040044377 March 4, 2004 Larsson et al.
20040064069 April 1, 2004 Reynolds et al.
20040077936 April 22, 2004 Larsson et al.
20040088015 May 6, 2004 Casavant et al.
20040111139 June 10, 2004 McCreery
20040186543 September 23, 2004 King et al.
20040210261 October 21, 2004 King et al.
20050004565 January 6, 2005 Vanney
20050013879 January 20, 2005 Lin et al.
20050021102 January 27, 2005 Ignagni et al.
20050033137 February 10, 2005 Oral et al.
20050043765 February 24, 2005 Williams et al.
20050070981 March 31, 2005 Verma
20050075578 April 7, 2005 Gharib et al.
20050085865 April 21, 2005 Tehrani
20050085866 April 21, 2005 Tehrani
20050085867 April 21, 2005 Tehrani et al.
20050085868 April 21, 2005 Tehrani et al.
20050085869 April 21, 2005 Tehrani et al.
20050096710 May 5, 2005 Kieval
20050109340 May 26, 2005 Tehrani
20050113710 May 26, 2005 Stahmann et al.
20050115561 June 2, 2005 Stahmann et al.
20050131485 June 16, 2005 Knudson et al.
20050138791 June 30, 2005 Black et al.
20050138792 June 30, 2005 Black et al.
20050143787 June 30, 2005 Boveja et al.
20050165457 July 28, 2005 Benser et al.
20050182454 August 18, 2005 Gharib et al.
20050187584 August 25, 2005 Denker et al.
20050192655 September 1, 2005 Black et al.
20050251238 November 10, 2005 Wallace et al.
20050251239 November 10, 2005 Wallace et al.
20050288730 December 29, 2005 Deem et al.
20060030894 February 9, 2006 Tehrani
20060035849 February 16, 2006 Spiegelman
20060058852 March 16, 2006 Koh et al.
20060074449 April 6, 2006 Denker et al.
20060122661 June 8, 2006 Mandell
20060122662 June 8, 2006 Tehrani et al.
20060130833 June 22, 2006 Younes
20060142815 June 29, 2006 Tehrani et al.
20060149334 July 6, 2006 Tehrani et al.
20060155222 July 13, 2006 Sherman et al.
20060167523 July 27, 2006 Tehrani et al.
20060188325 August 24, 2006 Dolan
20060195159 August 31, 2006 Bradley et al.
20060217791 September 28, 2006 Spinka et al.
20060224209 October 5, 2006 Meyer
20060229677 October 12, 2006 Moffitt et al.
20060247729 November 2, 2006 Tehrani et al.
20060253161 November 9, 2006 Libbus et al.
20060253182 November 9, 2006 King
20060258667 November 16, 2006 Teng
20060259107 November 16, 2006 Caparso et al.
20060282131 December 14, 2006 Caparso et al.
20060287679 December 21, 2006 Stone
20070005053 January 4, 2007 Dando
20070021795 January 25, 2007 Tehrani
20070027448 February 1, 2007 Paul et al.
20070087314 April 19, 2007 Gomo
20070093875 April 26, 2007 Chavan et al.
20070106357 May 10, 2007 Denker et al.
20070112403 May 17, 2007 Moffitt et al.
20070118183 May 24, 2007 Gelfand et al.
20070150006 June 28, 2007 Libbus et al.
20070168007 July 19, 2007 Kuzma et al.
20070173900 July 26, 2007 Siegel et al.
20070191908 August 16, 2007 Jacob et al.
20070196780 August 23, 2007 Ware et al.
20070203549 August 30, 2007 Demarais et al.
20070208388 September 6, 2007 Jahns et al.
20070221224 September 27, 2007 Pittman et al.
20070240718 October 18, 2007 Daly
20070250056 October 25, 2007 Vanney
20070250162 October 25, 2007 Royalty
20070255379 November 1, 2007 Williams et al.
20070265611 November 15, 2007 Ignagni et al.
20070288076 December 13, 2007 Bulkes et al.
20080065002 March 13, 2008 Lobl et al.
20080125828 May 29, 2008 Ignagni et al.
20080161878 July 3, 2008 Tehrani et al.
20080167695 July 10, 2008 Tehrani et al.
20080177347 July 24, 2008 Tehrani et al.
20080183186 July 31, 2008 Bly et al.
20080183187 July 31, 2008 Bly
20080183239 July 31, 2008 Tehrani et al.
20080183240 July 31, 2008 Tehrani et al.
20080183253 July 31, 2008 Bly
20080183254 July 31, 2008 Bly et al.
20080183255 July 31, 2008 Bly et al.
20080183259 July 31, 2008 Bly et al.
20080183264 July 31, 2008 Bly et al.
20080183265 July 31, 2008 Bly et al.
20080188903 August 7, 2008 Tehrani et al.
20080215106 September 4, 2008 Lee et al.
20080288010 November 20, 2008 Tehrani et al.
20080288015 November 20, 2008 Tehrani et al.
20080312712 December 18, 2008 Penner
20080312725 December 18, 2008 Penner
20090036947 February 5, 2009 Westlund et al.
20090118785 May 7, 2009 Ignagni et al.
20100022950 January 28, 2010 Anderson et al.
20100036451 February 11, 2010 Hoffer
20100077606 April 1, 2010 Black et al.
20100094376 April 15, 2010 Penner
20100114227 May 6, 2010 Cholette
20100198296 August 5, 2010 Ignagni et al.
20100268311 October 21, 2010 Cardinal et al.
20100319691 December 23, 2010 Lurie et al.
20110060381 March 10, 2011 Ignagni et al.
20110077726 March 31, 2011 Westlund et al.
20110118815 May 19, 2011 Kuzma et al.
20110230932 September 22, 2011 Tehrani et al.
20110288609 November 24, 2011 Tehrani et al.
20120053654 March 1, 2012 Tehrani et al.
20120078320 March 29, 2012 Schotzko et al.
20120158091 June 21, 2012 Tehrani et al.
20120209284 August 16, 2012 Westlund et al.
20120215278 August 23, 2012 Penner
20120323293 December 20, 2012 Tehrani et al.
20130018247 January 17, 2013 Glenn et al.
20130018427 January 17, 2013 Pham et al.
20130023972 January 24, 2013 Kuzma et al.
20130030496 January 31, 2013 Karamanoglu et al.
20130030497 January 31, 2013 Karamanoglu et al.
20130030498 January 31, 2013 Karamanoglu et al.
20130060245 March 7, 2013 Grunewald et al.
20130116743 May 9, 2013 Karamanoglu et al.
20130131743 May 23, 2013 Yamasaki et al.
20130158625 June 20, 2013 Gelfand et al.
20130165989 June 27, 2013 Gelfand et al.
20130167372 July 4, 2013 Black et al.
20130197601 August 1, 2013 Tehrani et al.
20130289686 October 31, 2013 Masson et al.
20130296964 November 7, 2013 Tehrani
20130296973 November 7, 2013 Tehrani et al.
20130317587 November 28, 2013 Barker
20130333696 December 19, 2013 Lee et al.
20140088580 March 27, 2014 Wittenberger et al.
20140114371 April 24, 2014 Westlund et al.
20140128953 May 8, 2014 Zhao et al.
20140148780 May 29, 2014 Putz
20140316486 October 23, 2014 Zhou et al.
20140324115 October 30, 2014 Ziegler et al.
20150034081 February 5, 2015 Tehrani et al.
20150045810 February 12, 2015 Hoffer et al.
20150045848 February 12, 2015 Cho et al.
20150119950 April 30, 2015 Demmer et al.
20150165207 June 18, 2015 Karamanoglu
20150250982 September 10, 2015 Osypka
20150265833 September 24, 2015 Meyyappan et al.
20150374252 December 31, 2015 De La Rama et al.
Foreign Patent Documents
0993840 April 2000 EP
1304135 April 2003 EP
0605796 August 2003 EP
2489395 August 2012 EP
2801509 June 2001 FR
H08510677 November 1996 JP
2003503119 January 2003 JP
9407564 April 1994 WO
9508357 March 1995 WO
9964105 December 1999 WO
9965561 December 1999 WO
0100273 January 2001 WO
02058785 August 2002 WO
2006110338 October 2006 WO
2006115877 November 2006 WO
2007053508 May 2007 WO
2008092246 August 2008 WO
2009006337 January 2009 WO
2012106533 August 2012 WO
2013131187 September 2013 WO
Other references
  • Amit K. Gupta, “Respiration Rate Measurement Based on Impedance Pneumography”, Texas Instruments, SBAA181—Feb. 2011, 11 pages.
  • L. Salmela et al., “Verification of the position of a central venous catheter by intra-atrial ECG, When does this method fail?”, Acta Anasthesiol Scand, 1993, vol. 37, Issue 1, pp. 26-28.
  • Antonica A., et al., “Vagal Control of Lymphocyte Release from Rat Thymus,” Journal of the Autonomic Nervous System, Elsevier, vol. 48(3), Aug. 1994, pp. 187-197.
  • Whaley K., et al., “C2 Synthesis by Human Monocytes is Modulated by a Nicotinic Cholinergic Receptor,” Nature, vol. 293, Oct. 15, 1981, pp. 580-582 (and reference page).
  • Borovikovaa L.V., et al., “Role of Vagus Nerve Signaling in CNI-1493-Mediated Suppression of Acute Inflammation,” Autonomic Neuroscience: Basic and Clinical, vol. 85 (1-3), Dec. 20, 2000, pp. 141-147.
  • Borovikovaa L.V., et al., “Vagus Nerve Stimulation Attenuates the Systemic Inflammatory Response to Endotoxin,” Nature, Macmillan Magazines Ltd, vol. 405, May 25, 2000, pp. 458-462.
  • Co-pending U.S. Appl. No. 15/606,867, filed May 26, 2017.
  • Extended European Search Report for Application No. 14864542.7, dated Jun. 2, 2017, 8 pages.
  • Fleshner M., et al., “Thermogenic and Corticosterone Responses to Intravenous Cytokines (IL-1β and TNF-α) are Attenuated by Subdiaphragmatic Vagotomy,” Journal of Neuroimmunology, vol. 86, Jun. 1998, pp. 134-141.
  • Gaykema R.P.A. et al., “Subdiaphragmatic Vagotomy Suppresses Endotoxin-Induced Activation of Hypothalamic corticotropin-Releasing Hormone Neurons and Acth Secretion,” Endocrinology, The Endocrine Society, vol. 136 (10), 1995, pp. 4717-4720.
  • Guslandi M., “Nicotine Treatment for Ulcerative Colitis,” The British Journal of Clinical Pharmacology, Blackwell Science Ltd, vol. 48, 1999, pp. 481-484.
  • Japanese Office Action in corresponding Japanese Application No. 2014-560202, dated Dec. 6, 2016, 4 pages.
  • Kawashima K., et al., “Extraneuronal Cholinergic System in Lymphocytes,” Pharmacology & Therapeutics, Elsevier, vol. 86, 2000, pp. 29-48.
  • Madretsma, G.S., et al., “Nicotine Inhibits the In-vitro Production of Interleukin 2 and Tumour Necrosis Factor-α by Human Mononuclear Cells,” Immunopharmacology, Elsevier, vol. 35 (1), Oct. 1996, pp. 47-51.
  • Nabutovsky, Y., et al., “Lead Design and Initial Applications of a New Lead for Long-Term Endovascular Vagal Stimulation,” PACE, Blackwell Publishing, Inc, vol. 30(1), Jan. 2007, pp. S215-S218.
  • Pavlovic D., et al., “Diaphragm Pacing During Prolonged Mechanical Ventilation of the Lungs could Prevent from Respiratory Muscle Fatigue,” Medical Hypotheses, vol. 60 (3), 2003, pp. 398-403.
  • Planas R.F., et al., “Diaphragmatic Pressures: Transvenous vs. Direct Phrenic Nerve Stimulation,” Journal of Applied Physiology, vol. 59(1), 1985, pp. 269-273.
  • Romanovsky, A.A., et al., “The Vagus Nerve in the Thermoregulatory Response to Systemic Inflammation,” American Journal of Physiology, vol. 273 (1 Pt 2), 1997, pp. R407-R413.
  • Sandborn W.J., “Transdermal Nicotine for Mildly to Moderately Active Ulcerative Colitis,” Annals of Internal Medicine, vol. 126 (5), Mar. 1, 1997, pp. 364-371.
  • Sato E., et al., “Acetylcholine Stimulates Alveolar Macrophages to Release Inflammatory Cell Chemotactic Activity,” American Journal of Physiology, vol. 274 (Lung Cellular and Molecular Physiology 18), 1998, pp. L970-L979.
  • Sato, K.Z., et al., “Diversity of mRNA Expression for Muscarinic Acetylcholine Receptor Subtypes and Neuronal Nicotinic Acetylcholine Receptor Subunits in Human Mononuclear Leukocytes and Leukemic Cell Lines,” Neuroscience Letters, vol. 266 (1), 1999, pp. 17-20.
  • Schauerte P., et al., “Transvenous Parasympathetic Nerve Stimulation in the Inferior Vena Cava and Atrioventricular Conduction,” Journal of Cardiovascular Electrophysiology, vol. 11 (1), Jan. 2000, pp. 64-69.
  • Schauerte P.N., et al., “Transvenous Parasympathetic Cardiac Nerve Stimulation: An Approach for Stable Sinus Rate Control,” Journal of Cardiovascular Electrophysiology, vol. 10 (11), Nov. 1999, pp. 1517-1524.
  • Scheinman R.I., et al., “Role of Transcriptional Activation of IκBα in Mediation of Immunosuppression by Glucocorticoids,” Science, vol. 270, Oct. 13, 1995, pp. 283-286.
  • Sher, M.E. et al., “The Influence of Cigarette Smoking on Cytokine Levels in Patients with Inflammatory Bowel Disease,” Inflammatory Bowel Diseases, vol. 5 (2), May 1999, pp. 73-78.
  • Steinlein, O., “New Functions for Nicotinic Acetylcholine Receptors?,” Behavioural Brain Research, vol. 95, 1998, pp. 31-35.
  • Sternberg E.M., (Series Editor) “Neural-Immune Interactions in Health and Disease,” The Journal of Clinical Investigation, vol. 100 (11), Dec. 1997, pp. 2641-2647.
  • Sykes., A.P., et al., “An Investigation into the Effect and Mechanisms of Action of Nicotine in Inflammatory Bowel Disease,” Inflammation Research, vol. 49, 2000, pp. 311-319.
  • Toyabe S., et al., “Identification of Nicotinic Acetylcholine Receptors on Lymphocytes in the Periphery as well as Thymus in Mice,” Immunology, vol. 92, 1997, pp. 201-205.
  • Van Dijk A.P.M., et al., “Transdermal Nicotine Inhibits Interleukin 2 Synthesis by Mononuclear Cells Derived from Healthy Volunteers,” European Journal of Clinical Investigation, vol. 28, 1998, pp. 664-671.
  • Watkins L.R., et al., “Blockade of Interleukin-1 Induced Hyperthermia by Subdiaphragmatic Vagotomy: Evidence for Vagal Mediation of Immune-Brain Communication,” Neuroscience Letters, vol. 183, 1995, pp. 27-31.
  • Watkins L.R., et al., “Implications of Immune-to-Brain Communication for Sickness and Pain,” PNAS (Proceedings of the National Academy of Sciences of the USA), vol. 96 (14), Jul. 6, 1999, pp. 7710-7713.
Patent History
Patent number: 10039920
Type: Grant
Filed: Sep 14, 2017
Date of Patent: Aug 7, 2018
Assignee: Lungpacer Medical, Inc. (Burnaby)
Inventors: Viral S. Thakkar (Burnaby), Douglas G. Evans (Downingtown, PA), Matthew J. Gani (Seattle, WA)
Primary Examiner: Brian T Gedeon
Application Number: 15/704,439
Classifications
Current U.S. Class: Stimulating Respiration Function (607/42)
International Classification: A61B 5/04 (20060101); A61N 1/36 (20060101); A61N 1/05 (20060101); A61B 5/042 (20060101); A61B 5/0452 (20060101); A61B 5/00 (20060101);